NACL/FLUID SECRETION BY MAMMALIAN RENAL COLLECTING DUCTS

细胞外液容量的维持需要体内盐分的摄取和排泄达到平衡。众所周知，哺乳动物肾脏中的肾小管和集合管在尿液形成过程中会重新吸收大量的氯化钠和液体。然而，一些研究表明，许多管段也可能具有净溶质和液体分泌的分子成分。因此，盐液平衡可能是分泌物大规模吸收和微调的结果。内髓集合管(IMCD)的理想位置是在尿液离开肾脏之前对其进行最后的调整。IMCD细胞具有顶端囊性纤维化跨膜传导调节蛋白(CFTR)氯通道，而原代培养的大鼠IMCD细胞在cAMP刺激下表现出电刺激的阴离子分泌。据我所知，人肾单位的氯化钠和液体分泌物还没有得到充分的检查。我将研究人类肾小管，特别是IMCD，能在多大程度上主动分泌(Na)Cl和液体，从而对ECV的调节做出贡献。

The maintenance of the extracellular fluid volume requires a balance NaCl intake and its excretion from the body. It is well established that renal tubules and collecting ducts in the mammalian kidney reabsorb large amounts of NaCl and fluid during urine formation. However, several studies suggest that many tubular segments may also have the molecular components for net solute and fluid secretion. Therefore, it is possible that salt and fluid balance is a consequence of large scale absorption and fine-tuning by secretion. The inner medullary collecting duct (IMCD) is ideally positioned to make the final adjustments to urine before it leaves the kidney. Cells from the IMCD possess apical cystic fibrosis transmembrane conductance regulator (CFTR) Cl channels and primary cultures from rat IMCD cells display electrogenic anion secretion stimulated by cAMP. To my knowledge, NaCl and fluid secretion by the human nephron have not been adequately examined. I will investigate the extent to which human renal tubules, notably the IMCD, can actively secrete (Na)Cl and fluid and thereby contribute to the regulation of ECV.